Field
Anti-copy optical materials, particularly for use in anti-counterfeiting applications, are disclosed. More particularly, embodiments related to anti-copy optical materials incorporating fluorescent materials and one or more optical absorbers configured to absorb visible light, are disclosed.
Background Information
Advances in document reproduction technology over the past several decades have led to an increase in the illicit reproduction and counterfeiting of documents worldwide. Such documents include, but are not limited to: banknotes, government bonds, identity documents such as passports and driver's licenses, bank checks, bills of sale, deeds, and prescriptions for pharmaceuticals. The evolution of new reprographic technology has spawned a new class of “casual counterfeiters” with limited, if any, traditional counterfeiting skills. These counterfeiters take advantage of the increased availability of advanced color copiers and color scanner-computer-printer systems to counterfeit, e.g., banknotes that can be passed off as authentic currency.
One difficulty in stopping such illicit reproduction is that platen-based scanners readily copy most of the low-cost, level one, anti-counterfeiting features that exist on banknotes and other documents. These reprographic systems, like a human viewer, detect light in a visible spectrum that is diffusely reflected from a document surface, to capture an image of the document. Since both photocopier systems and humans detect light in the visible spectrum, it is difficult to create a feature on the document that will be imaged differently by a photocopier system, than how the feature will be seen under white light by a user.
Current anti-counterfeiting measures rely mainly on manufacturers to install firmware in scanners that can recognize predefined document images, e.g., images of specific banknotes, and in response, to disable the photocopy process. However, such scanners can be readily retrofitted with other software lacking the anti-counterfeiting restriction, thus rendering attempts to prevent illicit reproduction useless.